The invention relates to the field of integrated circuit (IC) package and wafer design, as well as to the fields of interconnection, testing and burn-in structures and processes. More particularly, the invention relates to improvements in photolithography-patterned spring contacts and enhanced system interconnect assemblies having photolithography-patterned spring contacts for use in the testing or burn-in of integrated circuits, and for interconnecting a large number of signals between electronic systems or subsystems.
Integrated circuits are typically tested in wafer form (wafer sort) before they are packaged. During wafer sort, integrated circuits are tested one or few at a time, even though there may be hundreds or even thousands of the same integrated circuit located on a wafer. The packaged integrated circuits are then tested again, and burned-in, if necessary.
Prior to dicing the integrated circuits into individual dice on the wafer, the integrated circuits are placed (built) precisely on the wafer, but after dicing and separating the integrated circuits into individual dice for packaging and test, the packaged dices are handled individually, loosing the parallelism in handling.
Parallel testing on the wafer level has been limited in number and has so far been limited to low pin count devices, due to the difficulty in managing the large number of interconnects, and the limited amount of electronics which can conventionally be placed close to a wafer under test.
Attempts have also been made to burn-in ICs while in the wafer form. However, wafer-level burn-in is plagued with multiple problems, such as thermal expansion mismatch between the connector and the silicon wafer under test. Conventional structures, such as large area substrates having a large plurality of fanout traces which are electrically connected to pin or socket connectors, are typically implemented to manage connections between the IC under test, test electronics, and power management electronics.
The density of integrated circuits on semiconductor wafers continues to increase, due to semiconductor device scaling, with more gates and memory bits per unit area of silicon. As well, the use of larger semiconductor wafers (e.g. often having a nominal diameter of 8 inches or 12 inches) has become common. However, semiconductor test costs have increased on a cost per unit area of silicon basis. Therefore, semiconductor test costs have increased disproportionately over time, to become a greater percentage of the total manufacturing cost for each integrated circuit device.
Furthermore, advances in chip scale packaging (CSP) and other forms of small footprint packages have often made traditional packaged IC handlers obsolete for testing and burn-in.
In some conventional large surface area substrate integrated circuit (IC) test boards, electrical contacts between the test board and an integrated circuit wafer are typically provided by tungsten needle probes. However, tungsten needle probe technology is not able to meet the interconnect requirements of advanced semiconductors having higher pin counts, smaller pad pitches, and higher clock frequencies.
While emerging technologies have provided spring probes for different probing applications, most probes have inherent limitations, such as limited pitch, limited pin count, varying levels of flexibility, limited probe tip geometries, limitations of materials, and/or high costs of fabrication.
K. Banerji, A. Suppelsa, and W. Mullen III, Selectively Releasing Conductive Runner and Substrate Assembly Having Non-Planar Areas, U.S. Pat. No. 5,166,774 (24 Nov. 1992) disclose a runner and substrate assembly which comprises xe2x80x9ca plurality of conductive runners adhered to a substrate, a portion of at least some of the conductive runners have non-planar areas with the substrate for selectively releasing the conductive runner from the substrate when subjected to a predetermined stressxe2x80x9d.
A. Suppelsa, W. Mullen III and G. Urbish, Selectively Releasing Conductive Runner and Substrate Assembly, U.S. Pat. No. 5,280,139 (18 Jan. 1994) disclose a runner and substrate assembly which comprises xe2x80x9ca plurality of conductive runners adhered to a substrate, a portion of at least some of the conductive runners have a lower adhesion to the substrate for selectively releasing the conductive runner from the substrate when subjected to a predetermined stressxe2x80x9d.
D. Pedder, Bare Die Testing, U.S. Pat. No. 5,786,701 (28 Jul. 1998) disclose a testing apparatus for testing integrated circuits (ICs) at the bare die stage, which includes xe2x80x9ca testing station at which microbumps of conductive material are located on interconnection trace terminations of a multilayer interconnection structure, these terminations being distributed in a pattern corresponding to the pattern of contact pads on the die to be tested. To facilitate testing of the die before separation from a wafer using the microbumps, the other connections provided to and from the interconnection structure have a low profilexe2x80x9d.
D. Grabbe, I. Korsunsky and R. Ringler, Surface Mount Electrical Connector, U.S. Pat. No. 5,152,695 (06 Oct. 1992) disclose a connector for electrically connecting a circuit between electronic devices, in which xe2x80x9cthe connector includes a platform with cantilevered spring arms extending obliquely outwardly therefrom. The spring arms include raised contact surfaces and in one embodiment, the geometry of the arms provide compound wipe during deflectionxe2x80x9d.
H. Iwasaki, H. Matsunaga, and T. Ohkubo, Partly Replaceable Device for Testing a Multi-Contact Integrated Circuit Chip Package, U.S. Pat. No. 5,847,572 (08 Dec. 1998) disclose xe2x80x9ca test device for testing an integrated circuit (IC) chip having side edge portions each provided with a set of lead pins. The test device comprises a socket base, contact units each including a contact support member and socket contact numbers, and anisotropic conductive sheet assemblies each including an elastic insulation sheet and conductive members. The anisotropic conductive sheet assemblies are arranged to hold each conductive member in contact with one of the socket contact members of the contact units. The test device further comprises a contact retainer detachably mounted on the socket base to bring the socket contact members into contact with the anisotropic sheet assemblies to establish electrical communication between the socket contact members and the conductive members of the anisotropic conductive sheet assemblies. Each of the contact units can be replaced by a new contact unit if the socket contact members partly become fatigued, thereby making it possible to facilitate the maintenance of the test device. Furthermore, the lead pins of the IC chip can be electrically connected to a test circuit board with the shortest paths formed by part of the socket contact members and the conductive members of the anisotropic conductive sheet assembliesxe2x80x9d.
W. Berg, Method of Mounting a Substrate Structure to a Circuit Board, U.S. Pat. No. 4,758,927 (19 Jul. 1988) discloses xe2x80x9ca substrate structure having contact pads is mounted to a circuit board which. has pads of conductive material exposed at one main face of the board and has registration features which are in predetermined positions relative to the contact pads of the circuit board. The substrate structure is provided with leads which are electrically connected to the contact pads of the substrate structure and project from the substrate structure in cantilever fashion. A registration element has a plate portion and also has registration features which are distributed about the plate portion and are engageable with the registration features of the circuit board, and when so engaged, maintain the registration element against movement parallel to the general plane of the circuit board. The substrate structure is attached to the plate portion of the registration element so that the leads are in predetermined position relative to the registration features of the circuit board, and in this position of the registration element the leads of the substrate structure overlie the contact pads of the debit board. A clamp member maintains the leads in electrically conductive pressure contact with the contact pads of the circuit boardxe2x80x9d.
D. Sarma, P. Palanisamy, J. Hearn and D. Schwarz, Controlled Adhesion Conductor, U.S. Pat. No. 5,121,298 (09 Jun. 1992) disclose xe2x80x9cCompositions useful for printing controllable adhesion conductive patterns on a printed circuit board include finely divided copper powder, a screening agent and a binder. The binder is designed to provide controllable adhesion of the copper layer formed after sintering to the substrate, so that the layer can lift off the substrate in response to thermal stress. Additionally, the binder serves to promote good cohesion between the copper particles to provide good mechanical strength to the copper layer so that it can tolerate lift off without fracturexe2x80x9d.
R. Mueller, Thin-Film Electrothermal Device, U.S. Pat. No. 4,423,401 (27 Dec. 1983) discloses xe2x80x9cA thin film multilayer technology is used to build micro miniature electromechanical switches having low resistance metal-to-metal contacts and distinct on-off characteristics. The switches, which are electrothermally activated, are fabricated on conventional hybrid circuit substrates using processes compatible with those employed to produce thin-film circuits. In a preferred form, such a switch includes a cantilever actuator member comprising a resiliently bendable strip of a hard insulating material (e.g. silicon nitride) to which a metal (e.g. nickel) heating element is bonded. The free end of the cantilever member carries a metal contact, which is moved onto (or out on engagement with an underlying fixed contact by controlled bending of the member via electrical current applied to the heating elementxe2x80x9d.
S. Ibrahim and J. Elsner, Multi-Layer Ceramic Package, U.S. Pat. No. 4,320,438 (16 Mar. 1982) disclose xe2x80x9cIn a multi-layer package, a plurality of ceramic lamina each has a conductive pattern, and there is an internal cavity of the package within which is bonded a chip or a plurality of chips interconnected to form a chip array. The chip or chip array is connected through short wire bonds at varying lamina levels to metallized conductive patterns thereon, each lamina level having a particular conductive pattern. The conductive patterns on the respective lamina layers are interconnected either by tunneled through openings filled with metallized material, or by edge formed metallizations so that the conductive patterns ultimately connect to a number of pads at the undersurface of the ceramic package mounted onto a metalized board. There is achieved a high component density; but because connecting leads are xe2x80x9cstaggeredxe2x80x9d or connected at alternating points with wholly different package levels, it is possible to maintain a 10 mil spacing and 10 mil size of the wire bond lands. As a result, there is even greater component density but without interference of wire bonds one with the other, this factor of interference being the previous limiting factor in achieving high component density networks in a multi layer ceramic packagexe2x80x9d.
F. McQuade, and J. Lander, Probe Assembly for Testing Integrated Circuits, U.S. Pat. No. 5,416,429 (16 May 1995) disclose a probe assembly for testing an integrated circuit, which xe2x80x9cincludes a probe card of insulating material with a central opening, a rectangular frame with a smaller opening attached to the probe card, four separate probe wings each comprising a flexible laminated member having a conductive ground plane sheet, an adhesive dielectric film adhered to the ground plane, and probe wing traces of spring alloy copper on the dielectric film. Each probe wing has a cantilevered leaf spring portion extending into the central opening and terminates in a group of aligned individual probe fingers provided by respective terminating ends of said probe wing traces. The probe fingers have tips disposed substantially along a straight line and are spaced to correspond to the spacing of respective contact pads along the edge of an IC being tested. Four spring clamps each have a cantilevered portion which contact the leaf spring portion of a respective probe wing, so as to provide an adjustable restraint for one of the leaf spring portions. There are four separate spring clamp adjusting means for separately adjusting the pressure restraints exercised by each of the spring clamps on its respective probe wing. The separate spring clamp adjusting means comprise spring biased platforms each attached to the frame member by three screws and spring washers so that the spring clamps may be moved and oriented in any desired direction to achieve alignment of the position of the probe finger tips on each probe wingxe2x80x9d.
D. Pedder, Structure for Testing Bare Integrated Circuit Devices, European Patent Application No. EP 0 731 369 A2 (Filed 14 Feb. 1996), U.S. Pat. No. 5,764,070 (09 Jun. 1998) discloses a test probe structure for making connections to a bare IC or a wafer to be tested, which comprises xe2x80x9ca multilayer printed circuit probe arm which carries at its tip an MCM-D type substrate having a row of microbumps on its underside to make the required connections. The probe arm is supported at a shallow angle to the surface of the device or wafer, and the MCM-D type substrate is formed with the necessary passive components to interface with the device under test. Four such probe arms may be provided, one on each side of the device under testxe2x80x9d.
B. Eldridge, G. Grube, I. Khandros, and G. Mathieu, Method of Mounting Resilient Contact Structure to Semiconductor Devices, U.S. Pat. No. 5,829,128 (03 Nov. 1998), Method of Making Temporary Connections Between Electronic Components, U.S. Pat. No. 5,832,601 (10 Nov. 1998), Method of Making Contact Tip Structures, U.S. Pat. No. 5,864,946 (02 Feb. 1999), Mounting Spring Elements on Semiconductor Devices, U.S. Pat. No. 5,884,398 (23 Mar. 1999), Method of Burning-In Semiconductor Devices, U.S. Pat. No. 5,878,486 (09 Mar. 1999), and Method of Exercising Semiconductor Devices, U.S. Pat. No. 5,897,326 (27 Apr. 1999), disclose xe2x80x9cResilient contact structures are mounted directly to bond pads on semiconductor dies, prior to the dies being singulated (separated) from a semiconductor wafer. This enables the semiconductor dies to be exercised (e.g. tested and/or burned-in) by connecting to the semiconductor dies with a circuit board or the like having a plurality of terminals disposed on a surface thereof. Subsequently, the semiconductor dies may be singulated from the semiconductor wafer, whereupon the same resilient contact structures can be used to effect interconnections between the semiconductor dies and other electronic components (such a wiring substrates, semiconductor packages, etc.). Using the all-metallic composite interconnection elements of the present invention as the resilient contact structures, burn-in can be performed at temperatures of at least 150xc2x0 C., and can be completed in less than 60 minutesxe2x80x9d. While the contact tip structures disclosed by B. Eldridge et al. provide resilient contact structures, the structures are each individually mounted onto bond pads on semiconductor dies, requiring complex and costly fabrication. As well, the contact tip structures are fabricated from wire, which often limits the resulting geometry for the tips of the contacts. Furthermore, such contact tip structures have not been able to meet the needs of small pitch applications (e.g. typically on the order of 50 xcexcm spacing for a peripheral probe card, or on the order of 75 xcexcm spacing for an area array).
T. Dozier II, B. Eldridge, G. Grube, I. Khandros, and G. Mathieu, Sockets for Electronic Components and Methods of Connecting to Electronic Components, U.S. Pat. No. 5,772,451 (30 Jun. 1998) disclose xe2x80x9cSurface-mount, solder-down sockets permit electronic components such as semiconductor packages to be releaseably mounted to a circuit board. Resilient contact structures extend from a top surface of a support substrate, and solder-ball (or other suitable) contact structures are disposed on a bottom surface of the support substrate. Composite interconnection elements are used as the resilient contact structures disposed atop the support substrate. In any suitable manner, selected ones of the resilient contact structures atop the support substrate are connected, via the support substrate, to corresponding ones of the contact structures on the bottom surface of the support substrate. In an embodiment intended to receive an LGA-type semiconductor package, pressure contact is made between the resilient contact structures and external connection points of the semiconductor package with a contact force which is generally normal to the top surface of the support substrate. In an embodiment intended to receive a BGA-type semiconductor package, pressure contact is made between the resilient contact structures and external connection points of the semiconductor package with a contact force which is generally parallel to the top surface of the support substratexe2x80x9d.
Other emerging technologies have disclosed probe tips on springs which are fabricated in batch mode processes, such as by thin-film or micro-electronic mechanical system (MEMS) processes.
D. Smith and S. Alimonda, Photolithographically Patterned Spring Contact, U.S. Pat. No. 5,613,861 (25 Mar. 1997), U.S. Pat. No. 5,848,685 (15 Dec. 1998), and International Patent Application No. PCT/US 96/08018 (Filed 30 May 1996), disclose a photolithography patterned spring contact, which is xe2x80x9cformed on a substrate and electrically connects contact pads on two devices. The spring contact also compensates for thermal and mechanical variations and other environmental factors. An inherent stress gradient in the spring contact causes a free portion of the spring to bend up and away from the substrate. An anchor portion remains fixed to the substrate and is electrically connected to a first contact pad on the substrate. The spring contact is made of an elastic material and the free portion compliantly contacts a second contact pad, thereby contacting the two contact padsxe2x80x9d. While the photolithography patterned springs, as disclosed by Smith et al., are capable of satisfying many IC probing needs, the springs are small, and provide little vertical compliance to handle the planarity compliance needed in the reliable operation of many current IC prober systems. Vertical compliance for many probing systems is typically on the order of 0.004xe2x80x3-0.0100xe2x80x3, which often requires the use of tungsten needle probes.
While interposers have been used as an interconnecting structure, conventional interposers have been limited by pitch density, as well as by long term reliability over elevated temperatures, such as commonly seen in test or burn-in environments.
While probe substrates have been used as an interconnecting structure, such as for probing solder bumped wafers, the conventional probe substrates are often expensive, and/or require long lead times. Vertical probes, such as the Cobra Probe(trademark), are currently available from International Business Machines, of San Jose, Calif. A Microspring(trademark) probe assembly is currently available from Form Factor, Inc., of Livermore Calif.
T. Distefano, J. Smith and A. Faraci, Fixtures and Methods for Lead Bonding and Deformation, U.S. Pat. No. 6,080,603 (27 Jun. 2000), disclose xe2x80x9cIn a method for mounting a sheet-like microelectronic element, the sheet-like element comprises a dielectric layer having a top surface and a bottom surface and is first bonded to an expansion ring. The expansion ring is then heated to stretch the sheet-like element. A frame ring, having an external diameter smaller than the internal diameter of the expansion ring, is then bonded to the sheet-like element. A plurality of leads are formed on the bottom surface of the sheet-like element, the leads including bonding pads. In other embodiments, a method is provided for bonding bond pads on a sheet-like microelectronic element to contacts on a microelectronic component.xe2x80x9d
T. Distefano and J. Smith, Methods of Making Connections to a Microelectronic Unit, U.S. Pat. No. 6, 044,548 (04 Apr. 2000) disclose xe2x80x9cA method of making connections to a microelectronic unit includes the steps of providing a connection component having a flexible dielectric top sheet, a plurality of terminals on the top sheet and a plurality of electrically conductive, elongated flexible leads connected to the terminals and extending side-by-side downwardly from the terminals away from the top sheet to bottom ends remote from the top sheet. The connection component is then engaged with a front surface of a microelectronic unit having an array of contacts thereon while subjecting the connection component and the microelectronic unit to heat and pressure so that bottom ends of the leads remote from the top sheet bond with the contacts on the microelectronic unit to form electrical connections therewith.xe2x80x9d
M. Beroz, B. Haba and C. Pickett, Lead Formation Using Grids, U.S. Pat. No. 6,063,648 (16 May 2000) disclose xe2x80x9cA component for making microelectronic units includes a grid of interspersed leads with ends of the various leads being connected to one another by frangible elements. One end of each lead is bonded to a top element and the other end of each lead is bonded to a bottom element. The top and bottom elements are moved away from one another, thereby breaking the frangible elements and deforming the leads towards a vertically extensive disposition. A flowable composition such as dielectric material may be injected around the leads during or after the moving step. The resulting unit may be used to form permanent or temporary connections between microelectronic elements.xe2x80x9d
K. Gilleo, G. Grube and G. Mathieu, Compliant Semiconductor Chip Assemblies and Methods of Making Same, U.S. Pat. No. 6,020,220 (01 Feb. 2000) disclose xe2x80x9cA semiconductor chip package assembly is mounted to contact pads on a die. A compliant interposer layer is disposed between the die and a dielectric substrate wiring layer. The contacts on the die are connected to terminals on the compliant interposer layer by means of a compliant, conductive polymer extending through apertures in the interposer layer. Compliancy in the interposer layer and in the conductive polymer permits relative movement of the terminals on the dielectric substrate wiring layer to the contacts on the die and hence relieves the shear forces caused by differential thermal expansion. The arrangement provides a compact packaged structure similar to that achieved through flip-chip bonding, but with markedly increased resistance to thermal cycling damage. Further, the packaged structure allows the standardization of the packages such that several companies can make competing chips that are packaged such that the resultant packaged structures are roughly the same as far as the end user is concerned.xe2x80x9d
T. DiStefano, Z. Kovac and J. Smith, Bondable Compliant Pads for Packaging of a Semiconductor Chip and Method Therefor, U.S. Pat. No. 6,030,856 (29 Feb. 2000) disclose xe2x80x9cA method of making a microelectronic package includes providing first and second microelectronic elements having electrically conductive parts and disposing a resilient element having one or more intermediary layers capable of being wetted by an adhesive between the microelectronic elements. The resilient element includes fibrous material, a fibrous matrix and/or voids formed at the intermediary layers thereof. An adhesive is provided between the intermediary layers and the microelectronic elements. The adhesive is then cured while it remains in contact with the intermediary layers for bonding the resilient element and the microelectronic elements. The electrically conductive parts are then bonded together to form electrical interconnections. A microelectronic package comprising a resilient element including one or more intermediary layers capable of being wetted by an adhesive is also provided.xe2x80x9d
P. Bellaar, T. DiStefano, J. Fjelstad, C. Pickett and J. Smith, Microelectronic Component with Rigid Interposer, U.S. Pat. No. 6,002,168 (14 Dec. 1999) disclose xe2x80x9cA microelectronic component for mounting a rigid substrate, such as a hybrid circuit to a rigid support substrate, such as a printed circuit board. The microelectronic component includes a rigid interposer which may have a chip mounted on its first surface; a pattern of contacts on the rigid interposer; a flexible interposer overlying the second surface of the rigid interposer; a pattern of terminals on the flexible interposer; flexible leads; and solder coated copper balls mounted on the flexible interposer. The microelectronic component may have a socket assembly mounted on the first surface of the rigid interposer. The microelectronic component may be mounted on a rigid support substrate.xe2x80x9d
B. Eldridge, G. Grube, I. Khandros and G. Mathieu, Method of Making Contact Tip Structures, U.S. Pat. No. 5, 864,946 (02 Feb. 1999) disclose xe2x80x9cResilient contact structures are mounted directly to bond pads on semiconductor dies, prior to the dies being singulated (separated) from a semiconductor wafer. This enables the semiconductor dies to be exercised (e.g., tested and/or burned-in) by connecting to the semiconductor dies with a circuit board or the like having a plurality of terminals disposed on a surface thereof. Subsequently, the semiconductor dies may be singulated from the semiconductor wafer, whereupon the same resilient contact structures can be used to effect interconnections between the semiconductor dies and other electronic components (such as wiring substrates, semiconductor packages, etc.). Using the all-metallic composite interconnection elements of the present invention as the resilient contact structures, burn-in can be performed at temperatures of at least 150xc2x0 C., and can be completed in less than 60 minutes.xe2x80x9d
B. Eldridge, G. Grube, I. Khandros and G. Mathieu, Wafer-Level Test and Burn-In, and Semiconductor Process, U.S. Pat. No. 6,032,356, disclose xe2x80x9cResilient contact structures are mounted directly to bond pads on semiconductor dies, prior to the dies being singulated (separated) from a semiconductor wafer. This enables the semiconductor dies to be exercised (e.g., tested and/or burned-in) in) by connecting to the semiconductor dies with a circuit board or the like having a plurality of terminals disposed on a surface thereof. Subsequently, the semiconductor dies may be singulated from the semiconductor wafer, whereupon the same resilient contact structures can be used to effect interconnections between the semiconductor dies and other electronic components (such as wiring substrates, semiconductor packages, etc.). Using the all-metallic composite interconnection elements of the present invention as the resilient contact structures, burn-in can be performed at temperatures of at least 150xc2x0 C., and can be completed in less than 60 minutes.xe2x80x9d
D. Hembree, W. Farnworth and J. Wark, Force Applying Probe Card and Test System for Semiconductor Wafers, U.S. Pat. No. 6,078,186 (20 June 2000) disclose xe2x80x9cA probe card for testing a semiconductor wafer, a test method, and a test system employing the probe card are provided. The probe card includes: a substrate; an interconnect slidably mounted to the substrate; and a force applying mechanism for biasing contacts on the interconnect into electrical engagement with contacts on the wafer. The force applying mechanism includes spring loaded electrical connectors that provide electrical paths to the interconnect, and generate a biasing force. The biasing force is controlled by selecting a spring constant of the electrical connectors, and an amount of Z-direction overdrive between the probe card and wafer. The probe card also includes a leveling mechanism for leveling the interconnect with respect to the wafer.xe2x80x9d
It would be advantageous to provide a chip scale package structure which comprises compliant electrical interconnections which can be built directly on the integrated circuit wafer without additional packaging steps, and is compatible with current IC processing lines. It would also be advantageous to provide an interposer structure having compliant high density electrical interconnections which can be manufactured using batch processes. Furthermore, it would be advantageous to provide a probe contactor structure having compliant high density electrical interconnections at lower force than conventional interposer techniques, which can be manufactured using batch processes.
The round trip transit time between a device under test and conventional test equipment is often longer then the stimulus to response times of high speed electronic circuits. It would be advantageous to provide a test interface system which reduces this transit time, by placing high speed test electronics in close proximity of the device under test, while meeting space and cost constraints. Furthermore, it would be advantageous to provide a test interface system which minimizes the cost, complexity, tooling, and turn around time required to change the test structure for the testing of different devices. The development of such a system would constitute a major technological advance.
It would be advantageous to provide a test interface system which provides probe contact with many, hundreds, or even hundreds of thousands of pads for one or more separated devices which are mounted on a compliant wafer carrier, such as for massively parallel testing and/or burn-in applications, wherein the pads may be in close proximity of one another, with a minimum spacing approaching 1 mil or less, while providing a uniform force and minimizing pad damage over the entire wafer. It would also be advantageous to provide such a test interface system which organizes and manages the interconnections between the devices under test and the tester electronics, while maintaining signal integrity and power and ground stability, and assures that no two or more adjacent pads are contacted by a single test probe tip. Furthermore, it would be advantageous to provide such a test structure which preferably provides planarity compliance with the devices under test. The development of such a system would constitute a further technological advance.
In addition, it would be advantageous to provide such a test system which preferably provides continuous contact with many, hundreds, or even hundreds of thousands of pads for one or more devices on a compliant wafer carrier over a wide temperature range, while providing thermal isolation between the test electronics and the devices under test. As well, it would be advantageous to provide a system for separate thermal control of the test system and of the devices under test.
It would also be advantageous to provide a test interface system which may be used to detect power to ground shorts in any die quickly, and to isolate power from a die having a detected power to ground short, before damage is done to the test electronics. In addition, it would be advantageous to provide a test interface structure which can detect that the contacts to many, hundreds, or even hundreds of thousands of pads are reliably made and are each of the contacts are within the contact resistance specification, to assure that the self inductance and self capacitance of each signal line are below values that would adversely affect test signal integrity, and to assure that the mutual inductance and mutual capacitance between pairs of signal lines and between signal lines and power or ground lines are below values that would adversely affect test signal integrity. As well, it would also be advantageous to provide a test interface structure which provides stimulus and response detection and analysis to many, hundreds, or even thousands of die under test in parallel, and which preferably provides diagnostic tests to a failed die, in parallel with the continued testing of all other die.
Furthermore, it would be advantageous to provide a large array interface system which can reliably and repeatedly establish contact to many, hundreds, or even hundreds of thousands of pads, without the need to periodically stop and inspect and/or clean the probe interface structure.
It would also be advantageous to provide a system for massively parallel interconnections between electrical components, such as between computer systems, which utilize spring probes within the interconnection structure, to provide high pin counts, small pitches, cost-effective fabrication, and customizable spring tips. The development of such a method and apparatus would constitute a major technological advance.
Several embodiments of stress metal springs are disclosed, which typically comprise a plurality of stress metal layers that are established on a substrate, which are then controllably. patterned and partially released from the substrate. An effective rotation angle is typically created in the formed stress metal springs, defining a looped spring structure. The formed springs provide high pitch compliant electrical contacts for a wide variety of interconnection structures, including chip scale semiconductor packages, high density interposer connectors, and probe contactors. Several embodiments of massively parallel interface integrated circuit test assemblies are also disclosed, comprising one or more substrates having stress metal spring contacts, to establish connections between one or more separated integrated circuits on a compliant wafer carrier, and use one or more test modules which are electrically connected to the integrated circuits on the compliant wafer carrier through the substrates. The massively parallel interface assemblies provide tight pad pitch and compliance, and preferably enable the parallel testing or burn-in of multiple ICs. In some preferred embodiments, the massively parallel interface assembly structures include separable standard electrical connector components, which reduces assembly manufacturing cost and manufacturing time. These massively parallel interface structures and assemblies enable high speed testing of separated integrated circuit devices affixed to a compliant carrier, and allow test electronics to be located in close proximity to the integrated circuit devices under test. Preferred embodiments of the massively parallel interface assemblies provide thermal expansion matching to the wafer under test, and provide a thermal path for system electronic. Alternate massively parallel interface structures provide massively parallel connection interfaces, which may be used in a wide variety of circuitry, such as for interconnecting computers in a network, or for interconnecting other electronic circuitry.